Aug. 25, 2026
Waiting for a possible cancer diagnosis can be one of the most stressful experiences in a person's life. The Undiagnosed Mass Clinic (UMC) at Mayo Clinic in Arizona provides answers more quickly, helping patients avoid unnecessary delays and move forward with the right care.
In a recent study published in the Journal of Primary Care & Community Health, the UMC cut the time to diagnosis by more than half for patients with cancerous or potentially cancerous masses.
Here, Steven W. Ressler, M.D., an internist at Mayo Clinic in Arizona and director of the UMC, discusses the clinic's approach, practical strategies for accelerating diagnosis and when to refer patients with an undiagnosed mass.
What prompted Mayo Clinic to create the UMC in 2015?
We wanted to bring all of Mayo Clinic's strengths to bear for people with a possible cancer diagnosis. Without an expedited diagnostic process, patients may wait weeks for specialty appointments, imaging, biopsies and pathology results, all while wondering whether they have cancer. As my wife likes to say, "When God closes one door, he always opens another — but it's hell in the hallway." Our mission is to get patients out of that hallway and into a place of certainty.
The clinic is led by general internists with expertise in consultative medicine. In addition to diagnostic services, the UMC maintains a registry that combines a biospecimen repository with clinical and operational information to support future research efforts.
How does the Undiagnosed Mass Clinic help patients reach a diagnosis more quickly?
We approach the diagnostic process differently by doing as many things as possible — simultaneous rather than sequential efforts. When a patient comes to us, we immediately begin gathering records, reviewing imaging, planning additional testing and determining the appropriate biopsy approach. In many cases, we've already reviewed the scans and considered potential biopsy options before the patient arrives at the clinic. We like to approach this process as if we are "on the clock."'
Close collaboration with radiology is absolutely critical. Our radiology colleagues help us identify the safest biopsy site and the location most likely to provide enough tissue for a definitive diagnosis. We also work hard to avoid repeat procedures by collecting sufficient tissue the first time.
Managing a cancer diagnosis requires a precision oncology approach that often includes multiple genetic and other tests on tissue to help determine the most appropriate treatment. Throughout the process, we bring together the expertise of Mayo Clinic specialists across disciplines.
How can community physicians speed up diagnosis for patients with a newly discovered mass?
When a patient presents with a new mass or findings concerning cancer, it's already a race against the clock.
A few practical ways to accelerate the diagnostic process:
- Do things simultaneously, not sequentially.
- Decide on "sick or not sick" as soon as you can. If they're sick, don't spend time on an outpatient workup — admit them.
- Make a friend in radiology. Having a radiologist available for quick curbside consults can be invaluable for decision-making, biopsy planning and other diagnostic steps.
- Sharpen your expertise on differentials. Use online resources such as OpenEvidence and UpToDate to hone your decision-making skills.
If you have limited local resources or the diagnostic process is likely to take weeks, consider engaging a specialty center early. At the Undiagnosed Mass Clinic, many patients receive a diagnosis within days, not weeks.
Why is early cancer detection such a priority at Mayo Clinic right now?
Cancer rates continue to rise, and we know outcomes improve when we identify cancer earlier. The Undiagnosed Mass Clinic focuses on patients who already have a suspicious finding, but Mayo Clinic is also investing in technologies that may detect cancer before a mass or worrisome cancer symptoms ever develop. That's the goal of our Multicancer Detection Clinic, where our experts are evaluating blood-based tests that can identify signals of multiple cancers, often at earlier stages, potentially intercepting cancer at earlier and more treatable stages.
Together, these efforts reflect Mayo Clinic's broader commitment to accelerating cancer diagnosis and improving patient outcomes.
How can physicians request a UMC consult?
The easiest way is through Mayo Clinic's referring physician line. The referral team handles registration and logistics, while our clinical team begins reviewing the case, gathering records and obtaining imaging. We typically triage referrals the same day, allowing us to start the diagnostic process as quickly as possible.
For more information
Ressler SW, et al. Development of an undiagnosed mass registry: Lessons learned from our first 100 patients. Journal of Primary Care & Community Health. 2025;16:21501319251325650.
Refer a patient to Mayo Clinic.